To the Editor.—The use of pancreatic enzyme extracts has decreased maldigestion of fat, as well as macronutrients and micronutrients due to pancreatic insufficiency and alleviated various abdominal symptoms, including steatorrhea, pain associated with alcohol-induced chronic pancreatitis, and distal intestinal obstruction.1,2 Despite the recognized importance of pancreatic enzyme extracts, current preparations cannot be easily interchanged in clinical practice.3 A change in capsule with a similar level of lipase can cause an increase in steatorrhea.4,5 We decided to examine the level of several zymogen enzymes in the pancreatic extracts from two leading companies and to compare the findings (1) with the composition claimed by the manufacturers, (2) with whether there are differences in proteases (ie, trypsin, chymotrypsin, and carboxypeptidases A and B), and (3) to check the stability of the enzymes in 3-hour incubation time and release in pH 6.5 in phosphate buffer. Most patients with cystic fibrosis